Colored fog and process of forming same



United States Patent 2,699,386 Patented Jan. 11, 1955 ice Saul R. Buc,Easton, Pa., assignor to General Aniline & Film Corporation, New York,N. Y., a corporation of Delaware No Drawing. Application December 20,1950, Serial No. 201,877

6 Claims. (Cl. 52-23) The present invention relates to colored fog forsignaHing and other purposes.

Colored smokes are used by the armed forces for signalling and may alsohave application for advertising display purposes. These may includedyes or pigments suspended in the smoke.

Applicant has discovered a new colored fog and a method for producingit. The composition is a dyestuif suspended in a solvent for thedyestuff in the form of a fog. This is preferably prepared by sprayingtwo separate liquid intermediates in the air which combine to form adye.

The following examples illustrate preferred embodiments of theinvention, but it will be understood that variations and modificationsmay be made within the scope of the claims.

Example 1 A 10% alcoholic solution of furfural is forced through a fineorifice to form a mist or fog. A 10% alcoholic solution of aniline plusaniline hydrochloride in equivalent parts is likewise forced through ajet to form a fog or mist which is directed into the body of fog or mistcontaining furfural. The reaction takes place almost instantaneouslyforming a pink color in the mixed fogs. The reaction may be representedas follows:

NH: NHio L- In concentrated form this dyestuif is a deep red compoundthe nomenclature of which is N,N'-diphenyl-5- amino-4-hydroxypentadien-2,4-aldimine hydrochloride.

Alternatively, the furfural need not be in alcoholic solution. Theaniline and aniline-hydrochloride may be in solution in any solvent,therefore including the lolwer alcohols (methyl, ethyl, propyl), glycol,glycol et er, etc.

Example 2 A solution in Water of diazotized 1-amino-2-naphthol-4-sulfonic acid was forced through an orifice to form a fog. A10% solution in water of phenol adjusted to a pH of 10 with sodiumcarbonate was forced through an orifice to form a fog and caused to mixwith the fog containing the amine. Almost immediately there was formed alight blue fog. The dye formed in this reaction has the followingformula:

SOaH

In a similar manner other diazotizable amines may be coupled withvarious couplers which give a fast reaction.

For example, a nitro derivative of the diazotized amine of Example 2 maybe used, having a formula:

These diazo compounds may be coupled with phenols, resorcinol,phloroglucinol, alpha naphthol, beta naphthol, 2-naphthol-3-carboxylicamides, pyrazolones, etc.

It will be understood that the fogs will be mixed as by directing jetsof fog so as to come together and form one large body of fog. Besidesthe means suggested in the examples other means for forming fog may beused. For example, one or both of the dye components may be prepared inan aerosol bomb. The dyestuif in this case may be dissolved in the fogforming a low boiling liquid or may be dissolved in a solvent for thedye such as alco hol and water and then mixed with the low boilingliquid. Examples of low boiling liquids used in the preparation ofaerosol bombs include methylchloride, ethylchloride, dichlor difluormethane, dichlor fluormethane, trichlor fluormethane, dichlortetrafluorethane.

It will be further understood that the reaction of Example 1 may becarried out with other simple aromatic amines plus their hydrochloride.Thus, in place of aniline may be used toluidine, naphthylarnine,biphenylamine, etc.

I claim:

1. A colored fog comprising a finely divided suspension in air of liquiddroplets of a solution in a solvent of the compound:

2. A method for producing a colored fog comprising contacting in theatmosphere a suspension in air of liquid droplets of a color formingreagent in liquid form selected from the class consisting of diazotizedl-amino- 2-naphthol-4-sulfonic acid and a mono nitrated derivativethereof and a second suspension in air of liquid droplets of a colorcoupler compound selected from the class consisting of phenols,naphthols and pyrazolones.

3. A method for producing a colored fog comprising contacting in theatmosphere a suspension in air of liquid droplets of furfural and asecond suspension in air of liquid droplets of an alcoholic solution ofan equal part mixture of a primary carbocyclic aryl amine and thehydrochloride of said aryl amine, said mixture and furfural beingcapable of forming in situ a colored fog.

4. A process for producing a colored fog comprising contacting in theatmosphere a fog produced by injecting an alcoholic solution of furfuralthrough a small orifice and a fog produced by injecting through a smallorifice an alcoholic solution of a mixture of aniline and anilinehydrochloride.

5. A method for producing a colored fog comprising releasing from anaerosol bomb a suspension in air of liquid droplets of a color formingreagent selected from the class consisting of furfural, diazotized1-amino-2- naphthol-4-sulfonic acid and the mono nitrated derivativethereof, and contacting therewith liquid droplets released from anotheraerosol bomb containing an equal part mixture of a primary aryl amineand the hydrochloride of said aryl amine dissolved in an alcoholicsolvent, and liquid droplets selected from the group of phenols,naphthols, and pyrazolones, said furfural and mixture of aryl amine andaryl amine hydrochloride and said diazotized primary aromatic amine andone of the group of phenols, naphthols, and pyrazolones, being capableof forming in situ a colored dye.

6. A colored fog comprising a solid-in-gas suspension consisting of anascent colored solid selected from a class consisting ofN,N'-diaryl-5-amino-4-hydroxy pentadiening of H and -NO2 and Y is amember of the group consisting of phenols, naphthols and pyrazolones.

2,4-aldimi11e hydrochlorides and mono azo dyes having the followingstructural formula N=N-Y References Cited in the file of this patent\-OH 5 UNITED STATES PATENTS X 1,624,600 Hitt Apr. 12, 1927 FOREIGNPATENTS $0111 10 231,826 Great Britain July 23, 1925 wherein X is amember selected from the group consist-

1. A COLORED FOG COMPRISING A FINELY DIVIDED SUSPENSION IN AIR OF LIQUIDDROPLETS OF A SOLUTION IN A SOLVENT OF THE COMPOUND:
 2. A METHOD FORPRODUCING A COLORED FOG COMPRISING CONTACTING IN THE ATMOSPHERE ASUSPENSION IN AIR OF LIQUID DROPLETS OF A COLOR FORMING REAGENT INLIQUID FORM SELECTED FROM THE CLASS CONSISTING OF DIAZOTIZEDL-AMINO2-NAPHTHOL-4-SULFONIC ACID AND A MONO NITRATED DERIVATIVE THEREOFAND A SECOND SUSPENSION IN AIR OF LIQUID DROPLETS OF A COLOR COUPLERCOMPOUND SELECTED FROM THE CLASS CONSISTING OF PHENOLS, NAPHTHOLS ANDPYRAZOLONES.